The present disclosure generally relates to lighting control devices, network systems, and methodologies, including methods for providing closed-loop dimming control of such systems.
With respect to dimming control, some methods use arbitrary or poorly correlated 0 through 10V dimming signals, being applied and then adjusted manually, in order to achieve a specific fixture wattage or derivation of a dim voltage to fixture watts dimming command curve to be developed for every conceivable combination of LED drivers and light engines, in order to predict the appropriate dimming control voltage to be applied to achieve the desired fixture wattage.
Some fixture controls with dimming capability require both a photo control module (or “node”) and a separate dimming control module. In such arrangements, the photo control module and dimming control module may include separate unique device identifiers, which can be used to identify the individual module on the control network. To properly control and diagnose a particular fixture SKU (unique combination of driver style, driver voltage, driver min/max current, LED count, LED type, etc.), the input Wattage characteristics of said fixture SKU must be characterized over the entire 0-10V dimming control voltage range. Aspects of this characterization may include, the driver end-point voltage thresholds (where the lower dead band stops and the upper dead band starts), and the resultant fixture Wattage at each of these two dead band threshold voltages.
During asset installation, an activation process may capture an identifier for the node and the associated fixture's SKU. A node profile, specific to the fixture SKU, is then manually created, e.g. at a network operation center (NOC), containing the dead band voltage thresholds. The node profile is pushed from the NOC to the node via the control network, and stored in the memory of the node.
A diagnostic table within the NOC must also be manually populated with a record containing: SKU (X), the fixture Wattage at each dead band threshold voltage, and node-internal digital codes that correspond to the two dead band voltage thresholds. Within the activation record for each node-equipped asset, the control module device and dimming control module device identifiers must also be paired (manually).
When daily fixture diagnostics are performed, the NOC must predict the expected dimmed fixture Wattage by referring to events/commands issued to/from the paired node identifiers, observing the dim command active during hourly time slices during the diagnostic period. The prediction may be derived using y=mx+b parameters stored in the NOC table. The NOC then compares this prediction to the actual reported fixture Watts from the node identifier to determine fixture status.
However, as with other human processes, aspects of current techniques may be relatively labor intensive, particularly for large-scale lighting systems, and allow for error related to, for example, fixture status and/or design changes, manual information entry and/or changes to, misidentification, and/or unrecognized system components, etc. There may also be problems pairing the identifiers of the specific control module and dimming control module for a given fixture in the NOC database/table. Moreover, many of these problems may be difficult to detect or correct, particularly in a large-scale networked lighting control system.